Some vehicle lights such as vehicle headlights are conventionally known to employ a light source which includes a semiconductor light-emitting element and a wavelength conversion material such as a phosphor (for example, see Japanese Patent No. 4124445). In the vehicle light of this type, the phosphor is irradiated with excitation light (for example, blue light) from the semiconductor light-emitting element, so that the light (for example, yellow light) emitted by the phosphor being excited is mixed with the excitation light to transmit a visible radiation (for example, white light), which is then projected as forward illumination for the vehicle through an optical system such as a projection lens.
However, in the aforementioned conventional vehicle light, part of the excitation light may be regularly reflected from the phosphor so as to be transmitted through the projection lens as it is without being mixed with a predetermined color, thus causing partial color variations to occur in the projected image (for example, light distribution pattern).